It's random when you play casual. Doesn't matter if you are good or not.
Its random after every match you play i have got a few good skins from playing but i find earning them on sites like this is a lot easier!
They are really good, if you wanna trade em, let me know.
Nevermind, they are of no value, lol.
I only get sprays and cases
Well, I got 4 cases, 2 skins and 2 sprays in like 3 weeks
i totally agree with
farmingbest.
Its random
game play random drop 
Game hag=best
random drops man
How do i get gems
cs go is the best
in 3 steps
Choose the game that interests you and play itfor free.
Every game has some quests for which you will receive Soul Gems.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
You know that on Gamehag you can get real rewards for free, right? Join us, complete walkthrough and get your chest!
You can get skins for guns and cases and spays if you were good at that game!